OUCH.
Have you considered setting up a Hoop coop on a temporary basis??? Inexpensive, roomy, the arc is good for snow loads - if you only need a season out of it, a tarp will do for the roof, offering a covered run. They are pretty quick to build, too.
Suppliment the sides with hardware cloth to keep your birds in, and the foxes out. Point the back wall at the prevailing winter winds, partially wall two sides (or tarp), and you are about there. Or build a pony wall inside your barn (if you have the space) to partition them off, a door to the outside thru the barn wall, and a covered (or at least netted) run.
This is a much better option than prefabs of any type.
Here are some articles on hoop coops:
https://www.backyardchickens.com/articles/hoop-tractor.69336/
https://www.backyardchickens.com/articles/hoop-coop-brooder-with-roll-up-sides.75720/
https://www.backyardchickens.com/articles/the-biddie-bordello-a-hoop-coop-run-combo.72189/reviews
https://www.backyardchickens.com/articles/permanent-hoop-coop-guide.47818/reviews